Matt Damon plays Blackjack on Jimmy Kimmel Live

Before Matt Damon popped up, Monday’s Jimmy Kimmel Live was supposed to be all about Aunt Chippy.

“Let’s go to my Aunt Chippy, who is at the Cosmopolitan of Las Vegas,” said Kimmel, cutting to a camera inside the casino. “Aunt Chippy is there to play Blackjack for you. And if she wins, you win.”

Chippy has a history of winning big — in fact, she scored $100,000 the first time she played for Kimmel’s studio audience. With Monday’s audience members psyched about their odds, Kimmel explained the rules. But then the camera angle widened, revealing Damon sitting next to Chippy.

“Hold on — there’s not supposed to be anyone else at the table,” Kimmel said to Damon, who attempted to go incognito in a Billy Ray Cyrus-style mullet wig and Ray-Ban sunglasses.

“If I knew he was going to be here, I would’ve shaved my legs, Jimmy,” cracked a thrilled Aunt Chippy.

Damon went on to explain that he was in Sin City for the world premiere of Jason Bourne. “Thought maybe I’d play some cards with Aunt Chippy,” said Damon. “I don’t know — is that a crime?”

Kimmel accepted it and the game finally began, but things didn’t look so great after Damon and Aunt Chippy agreed that they were “gonna have to take a hit.” Aunt Chippy lost all her money, and Kimmel was infuriated.

“Now we have no money, and I’m going to tell you why: because Matt Damon showed up,” Kimmel explained. “He took all your money from you, and now we have nothing.”

But Damon was feeling generous. “Hang on. Wait a minute. Jimmy, I was thinking, you know. I don’t know if you’ve ever seen $10,000, but I personally like your studio audience a lot, and I feel like some of them like me,” said Damon. “I think we’ve gotta do this again.”

With Damon’s extra cash, Chippy was able to give it another go. When the situation took a turn for the worse again, Damon came to the rescue — but Chippy didn’t get what she wanted.